Some simple algorithm programs in php (bubble, fast, etc.), php algorithm program bubbling_PHP tutorial

<span>function</span> buttle_sort(<span>$array</span><span>) {
        </span><span>$len</span>=<span>count</span>(<span>$array</span><span>);
        </span><span>if</span>(<span>$len</span><2<span>){
            </span><span>return</span> <span>$array</span><span>;
        }
        </span><span>for</span>(<span>$i</span>=0;<span>$i</span><<span>$len</span>;<span>$i</span>++<span>){
            </span><span>$flag</span> = <span>false</span>;<span>//</span><span>本趟排序开始前，交换标志应为假</span>
            <span>for</span>(<span>$j</span>=<span>$len</span>-1;<span>$j</span>><span>$i</span>;<span>$j</span>--<span>){
                </span><span>if</span>(<span>$array</span>[<span>$j</span>]<<span>$array</span>[<span>$j</span>-1<span>]){
                    </span><span>$tmp</span> = <span>$array</span>[<span>$j</span><span>];
                    </span><span>$array</span>[<span>$j</span>] = <span>$array</span>[<span>$j</span>-1<span>];
                    </span><span>$array</span>[<span>$j</span>-1] = <span>$tmp</span><span>;
                    </span><span>$flag</span> = <span>true</span>;<span>//</span><span>发生了交换，故将交换标志置为真</span>
<span>                }
            }
        }
        </span><span>if</span>(!<span>$flag</span>)<span>//</span><span>本趟排序未发生交换，提前终止算法</span>
            <span>return</span> <span>$array</span><span>;
        
    }</span>